A liquid crystal display device attracts attention due to advantages such as light weight, thin form, low power consumption, and the like. An active-matrix type liquid crystal display device includes a liquid crystal layer held between a pair of substrates which face each other, and a display portion constituted by a plurality of pixels arranged in a matrix form. At the display portion, One of the pair of substrates includes scanning lines arranged along row lines in which the pixels are arranged, and signal lines arranged along column lines in which the pixels are arranged. An alignment state of the liquid crystal molecules contained in the liquid crystal layer is controlled by an electrical field applied to the liquid crystal layer.
In particular, liquid crystal display devices of an IPS (In-Plane Switching) method and a FFS (Fringe Field Switching) method have advantages such as wide view angle and low power consumption, and are widely applied for the purposes of displays such as television sets and portable telephones. Such liquid crystal display devices includes a plurality of first electrodes (pixel electrode) arranged in the matrix form and a second electrode (common electrode) that faces the first electrodes on one of the pair of substrates, and the state of an alignment of the liquid crystal molecules contained in the liquid crystal layer is controlled by the horizontal electrical field generated between the first and second electrodes.
In particular, recently, a demand for providing a user interface on a display surface for improving operability is increasing, and products with a contact sensing element on the display surface of the liquid crystal display device are expanding in the market.